A product of Manchester United's youth academy, Campbell progressed to their first-team in the 2006–07 season, making two appearances without scoring in his tenure at the club. He had a loan spell at Belgian club Royal Antwerp, where he scored 21 goals in 33 games. He also had loan periods with Hull City and Tottenham Hotspur, where he scored 15 goals in 34 matches and one goal in ten games respectively. He signed for Sunderland at the beginning of the 2009–10 season for £3.5&nbsp;million.